Fuel injection pump

ABSTRACT

A fuel injection pump is located in a distributor housing which also contains a magnetic pickup for controlling fuel injection, a magnetic pickup for controlling ignition, and other ignition system components. The fuel injection pump is a variable displacement vane pump and has an accumulator and pressure regulator unit which maintains the fuel supplied to the injection nozzles at a constant pressure.

United States Patent 1 Guetersloh [s41 FUEL INJECTION PUMP [75]lnventor: Donald G. Guetersloh, Anderson,

Assignee: General I Motors Corporation,

Detroit, Mich.

Filed: net. 27, 1971 Appl. No.: 211,934

US. Cl. ..4l7/220, 417/307, 417/308, 417/310, 417/311, 418/31, 418/26Int. Cl ..F04b 49/08 Field of Search ..417/220, 310, 307, 308, 311;418/31, 26

References Cited UNITED STATES PATENTS 2,189,210 2/1940 Johnson..417/311 3,238,884 3/1966 Wright ..417/220 22 FUEL FROM SUPPLY [1113,724,972 51 Apr. 3, 1973 Primary Examiner-Carlton R. Croyle AssistantExaminer- Richard J. Sher Attorney-J. Carpenter et al.

[57] ABSTRACT A fuel-injection pump is located in a distributor hous-'ing which also contains a magnetic pickup for controlling fuelinjection, a magnetic pickup for'controlling ignition, and otherignition system components. The fuel injection pump is a variabledisplacement vane pump and has an accumulator and pressure regulatorunit which maintains the fuel supplied to the injection nozzles at aconstant pressure.

7 Claims, 3 Drawing Figures BIAS PATENTEUAPR 3 I975 SHEET 2 [1F 2 FUELRETURN 2 FUEL FROM SUPPLY 20 ACCUMULATOR REGULATOR [N VENTOR 30min(iuezeralolz ATTORNEY In some speed-density fuel injection systems,'fuelis metered by-opening an injection nozzle shortly before each combustionevent for a period of time determined by the absolute pressure in theair induction manifold. With these systems, it often is desired tomaintain the pressure of the fuel supplied to the injection nozzle at aconstant level so that fuel delivery is not afi'ected by variations infuel pressure. This invention provides an pressure regulator responds toexcessive fuel pressure accumulator and pressure regulator unit whichbyopening a valve to bleed fuel from the pump outlet.

The fuel so discharged may be utilized to move the slider and reduce thepump displacement, thereby avoiding pumping and recirculating excessfuel.

The accumulator and pressure regulator unit depicted herein includes alost motion connection between a rolling diaphragm and the pressurerelief valve so that a quantity of fuel is accumulated before excessivefuel'pressure causes the diaphragm to open the pressure relief valve.Upon an increase in demand for fuel, there is a tendency for the fuelpressure to The details as well as other objects and advantages of ithis invention are set forth in the remainder of the specification andin the drawings in which: I

FIG. 1 is an elevational view, in section, of a distributor assemblyincorporating the fuel injection pump and the accumulator and pressureregulator unit;

FIG. 2 is a sectional view along line 2-2 of FIG. 1 showing theinjection pump and the accumulator and pressure regulator unit; and

FIG. 3 is a schematic diagram of a fuel injection system incorporatingthe pump and the accumulator and pressure regulator of FIG. 2.

Referring first to FIG. 1, the distributor 10 has a base i 12 adaptedfor mounting on an engine and a shaft 14 driven from the engine througha gear 16.

An injection pump assembly 18 is mounted on base 12, and an accumulatorand pressure regulator unit 20 is secured to pump 18. I r

A housing 22, also mounted on base 12, contains a magnetic pickup coil24. Associated with coil 24 are a plurality of magnets 26 mounted on asleeve 28 keyed to shaft 14. Magnets 26 and coil 24 provide a timingsignal for an electronically controlled fuel injection system asdescribed in detail in U.S. Pat. No. 3,606,869.

An ignition distributor shell 30, mounted on housing 22, contains anignition distributor rotor 32, a centrifugal advance mechanism 34, avacuum advance mechanism 36 and a magneticpickup assembly 38, all asshown and described in detail in U.S. Pat. No. 3,254,247.

A distributor cap 40, mounted on distributor shell 30, contains anignition coil 42 as shown and described in detail in U.S. applicationSer. No. 38,988 filed May those patents are incorporated herein byreference and further discussion of those items is omitted.

It should be noted that housing 22 may be rotatably adjusted withrespect to distributor base 12 without moving fuel injection pump 18 andaccumulator and pressure regulator 20. This permits positioning of themagnetic pickups for the fuel injection and ignition systems to adjustfuel injection and ignition timing without requiring movement of thefuel lines associated with pump 18 and accumulator and pressureregulator unit 20.

Referring now to FIG. 2, injection pump 18 has a housing 44 forming acavity or chamber 46 which includes a pair of flat parallel surfaces'48and 50.

- A slider 52 is disposed within chamber 46 in sliding engagement withsurfaces 48 and 50. Slider 52 includes a cylindrical pumping chamber 54.

. A cylindrical rotor 56, pressed on sleeve 28 of shaft 14, is disposedin slider chamber 54. A plurality of vanes 58, disposed in slots 60 ofrotor 56, are biased outwardly by springs 62 into engagement with thecylindrical wall 64 of slider chamber 54.

Asshown in FIG. 3, a fuel line 66 delivers fuel to pump 18 from a supplypump 68 located in a fuel tank 70. Fuel is received from line 66 throughan inlet 72 in housing 44 and an inlet 74 in slider 52. Uponcounterclockwise-rotation of shaft 14, sleeve 28, and rotor 56, fuel isdelivered through pumping chamber 54, 'anoutlet 76 in slider 52, and anoutlet 78 in housing 44 to accumulator and pressure regulator unit 20.

As also shown in FIG. 3, fuel is delivered from accumulator and pressureregulator unit 20 through a fuel rail 80 to a plurality of injectionnozzles 82 As shown in FIG. 2, fuel is received from pump outlet 78 inan accumulator chamber 84. Accumulator chamber 84 is defined by ahousing 86 having a. closed end wall 88 and an otherwise open end 90closed by a pressure responsive rolling diaphragm 92. A fuel deliveryoutlet 94 is connected to fuel rail 80 and has'a spring biased .ballcheck valve 96 which prevents backflow from fuel rail 80 intoaccumulator chamber 84.

Accumulator chamber 84 also has a pressure relief outlet 98 opening fromclosed end 88. Pressure relief outlet 98 is connected by a passage 100to stator chamber 46 at one end 102 of slider 52. A spring 104 actsagainst the other end 106 of slider 52 to bias slider 52 against thefuel pressure acting against slider end chamber 84. Fuel is accumulatedin chamber 84 until pressure relief valve tangs 114 are engaged by theends of bracket slots 112. The accumulating stroke of diaphragm 92 isdetermined by the lost motion distance provided in slots 112. Movementof diaphragm 92 in excess of that distance causes disengagement of pressure relief valve 116 from pressure relief outlet 98, permitting excessfuel in accumulator chamber 84 to be discharged through outlet 98.

If desired, fuel discharged through pressure relief outlet 98 may bereturned to fuel pump inlet 72 or fuel tank 70. Preferably, however,fuel discharged through pressure relief outlet 98 is delivered throughpassage 100 to stator chamber 46 and acts on end 102 of slider 52. Thisdisplaces slider 52 against the bias of spring 104 to reduce theeccentricity between pumping chamber wall 64 and pump rotor 56. Thedelivery of injection pump 18 is thereby reduced to maintain the fuelpressure in accumulator 84, outlet 94, and fuel rail 80 at a constantvalue.

As injection nozzles 82 deliver an increased amount of fuel, the fuelpressure in fuel rail 80, outlet 94, and accumulator chamber 84 willtend to decrease. In response, diaphragm 92 is moved toward the bottomof FIG. 2 by spring 110, and the accumulated fuel in chamber 84 isdelivered though outlet 94 past check valve 96 to fuel rail 80. At thesame time, a spring 117 causes pressure relief valve 116 to engagepressure relief outlet 98, and the fuel pressure against slider end 102is dissipated through a restricted passage 118 in slider 52 to pumpingchamber inlet 74. Slider 52 then is returned by spring 104, and thedisplacement of pump 18 is increased to supply the increased fueldelivered by nozzles 82.

If desired, rolling diaphragm spring 110 may be received on a seat 120which is positioned by an adjustment 122 to control the preload ofspring 110 and thus to control the pressure range in which accumulatorand pressure regulator unit is effective.

On the opposite side of diaphragm 92 from accumulator chamber 84 is abias pressure chamber 124. Bias pressure chamber 124 may be maintainedat atmospheric pressure if desired. Preferably, however, a bias pressureis applied to chamber 124 which is the same in value as the pressureambient the outlet of injection nozzles 82. If injection nozzles 82discharge into an air induction manifold, then manifold pressure wouldbe applied to bias pressure chamber 124. And if injection nozzles 82discharge into an air gallery leading to an induction air manifold, thenair gallery pressure would be applied to bias pressure chamber 124. Bythis means, the pressure differential across injection nozzles 82 isalso applied across diaphragm 92 and the pressure differential acrossinjection nozzles 82 is thereby maintained constant.

It will be noted thatbracket 108 serves both to limit movement ofdiaphragm 92, by engaging end wall 88, and to operate pressure reliefvalve 116. It will be appreciated, however, that these functions may beseparated into two subassemblies. For example, the stop function ofbracket 108 could be achieved by having a portion engage the ledge 126;ledge 126 may be considered as a portion of end wall 88 for thispurpose.

In one application, accumulator and pressure regulator 20 is designed tomaintain the pressure in fuel rail at a level of 65 psi. In the eventpressure in outlet 76-78 should rise substantially above this level, aspring biased ball check valve 128, disposed in pump housing 44, opensto discharge fuel from outlet 78 through a passage 130. This fuel may bedischarged past the end 106 of slider 52 and returned to the pump inlet74 through an unrestricted passage 132 in slider 52. If desired, fuel sobypassed also may be returned through an outlet 134 in housing 44 and areturn line 136 to fuel tank 70.

As shown in FIG. 1, pump 18 is provided with top and bottom plates 138and 140 which form end walls for pumping chamber 54. Slider 52 and vanes58 are formed of carbon while rotor 56 and top and bottom plates 138 and140 are formed of sintered iron. These materials have been selected topermit efficient, durable pump operation.

I claim:

1. In a fuel injection system having a pump for delivering fuel to aninjection nozzle, an accumulator and pressure regulator for controllingdelivery of fuel from said pump to said nozzle and comprising a housingdefining a chamber for receiving fuel from said pump and having an openend and a closed end, said housing further defining a fuel deliveryoutlet extending from said chamber for delivering fuel to said nozzleand a pressure relief outlet extending from said closed end of saidchamber for discharging excess fuel received from said pump,

a rolling diaphragm closing said open end of said chamber and movableaway from said closed end of said chamber in response to an increase infuel pressure within said chamber,

. means biasing said diaphragm toward said closed end of said chamber,

a bracket secured to said diaphragm within said chamber and engageablewith said closed end of said chamber for limiting movement of saiddiaphragm theretoward,

a valve member disposed in said chamber and engageable with saidpressure relief outlet for controlling flow therethrough,

means biasing said valve member away from said diaphragm towardengagement with said pressure relief outlet,

said valve member including means engageable with said bracket aftersaid diaphragm and said bracket move a selected distance away from saidclosed end of said chamber to thereby disengage said valve member fromsaid pressure relief outlet,

whereby initial displacement of said diaphragm less than said selecteddistance in response to an increase in fuel pressure within said chamberincreases the amount of fuel accumulated in said chamber,

whereby additional displacement of said diaphragm greater than saidselected distance in response to an increase in fuel pressure withinsaid chamber effects disengagement of said valve member from saidpressure relief outlet to prevent further increase in pressure withinsaid chamber,

and whereby return of said diaphragm toward said closed end of saidchamber upon a decrease in fuel pressure within said chamber dischargesthe increased amount of fuel accumulated within said chamber throughsaid fuel delivery delivery to said nozzle.

2. The accumulator and pressure regulator of claim 1 wherein saidbracket has a plurality of slots and said valve member has projectionsreceived in said slots whereby said valve member may be engaged by saidbracket after said diaphragm and said bracket move said selecteddistance. i

3. The accumulator and pressure regulator of claim 1 which furthercomprises means for applying a bias pressure against said diaphragm inopposition to the fuel pressure. a

4. In a fuel injection system, a pump for delivering fuel to aninjection nozzle comprising a stator defining a stator chamber,

a cylindrical rotor disposed within said stator chamber, sliderreciprocably disposed within said stator chamber and having acylindrical pumping chamber receiving said rotor, said slider furtherhaving a fuel inlet for supplying fuel to said pumping chamber and afuel outlet for discharging fuel outlet for from said pumping chamber,said slider being responsive to an increase in fuel pressure in saidstator chamber to move from a pumping position wherein the axis of saidpumping chamber is eccentric the axis of said rotor toward a neutralposition wherein the axis of said pumping chamber is coincident the axisof said rotor,

means biasing said slider toward said pumping position,

a plurality of vanes extending radially from said rotor intoengagement-with said slider, an accumulator and pressure regulatorhaving an accumulator chamber connected to said slider fuel outlet forreceiving 'fuel from said pumping chamber, said accumulator chamberhaving an .open end, a closed end, a fuel delivery outlet for deliveringfuel to said nozzle and a pressure relief outlet extending to saidstator chamber at oneend of said slider, I

a rolling diaphragm closing said open end of said accumulator, chamberand movable away from said closed end upon an increase in fuel pressurewithin said accumulator chamber,

means biasing said diaphragm toward said closed end of said accumulatorchamber, v

a bracket secured to said diaphragm in said accumulator chamber andengageable with said closed end of said chamber for limiting movement ofsaid diaphragm theretoward, a valve member disposed in, said accumulatormeans biasing said valve member away from said diaphragm towardengagement with said pressure relief outlet,

said valve member including means engageable with said bracket aftersaid diaphragm and said bracket move a selected distance away from saidclosed end of said accumulator chamber to thereby disengage said valvemember from said pressure relief outlet, whereby rotation of said rotorwithin said pumping chamber when said slider is in said pumping position may effect delivery of fuel from said slider fuel .inlet, throughsaid pumping chamber, said slider fuel outlet, said accumulator chamber,and said fuel delivery outlet to said nozzle,

whereby initial displacement of said diaphragm less than said selecteddistance in response to an increase in fuel pressure within saidaccumulator chamber increases the amount of fuel accumulated in saidaccumulator chamber,

whereby additional displacement of said diaphragm greater than saidselected distance in response to an increase in fuel pressure withinsaid chamber eflects disengagement of said valve member from saidpressure relief outlet and fuel is discharged from said accumulatorchamber through said pres sure relief outlet to said stator chamber todisplace said slider toward said neutral position and thereby reduce,fuel delivery from said pumping chamber,

and whereby return of said diaphragm toward said closed end of saidchamber upon a decrease in fuel pressure said accumulator chamberdischarges the increased amount of fuel accumulated said accumulatorchamber through said fuel delivery outlet for delivery to saidnozzle.

5. The pump of claim 4 wherein said one end of said slider has anopening from said stator chamber to said slider fuel inlet to permitreduction of pressure in said stator chamber and thereby facilitatereturn of said slider to said pumping position under the bias of saidslider biasing means. I

6. The pump of claim 4 wherein said stator includes a pressure reliefpassage extending'from said slider fuel outlet to said stator chamber atthe opposite end of said slider, and which further comprises a pressureresponsive valve in said passage which permits fuel flow therethroughonly when thepressure in said fuel outlet exceeds a selected value,whereby excess pressure in said fuel outlet may be relieved.

7. The pump of clairn'6 wherein said opposite end of said slider has anopening from said stator chamber to said slider fuel inlet to allow fueldischarged past said chamber and engageable with said pressure reliefpressure responsive valve to flow freely to said fuel inlet.- I

0- s a a: s

1. In a fuel injection system having a pump for delivering fuel to aninjection nozzle, an accumulator and pressure regulator for controllingdelivery of fuel from said pump to said nozzle and comprising a housingdefining a chamber for receiving fuel from said pump and having an openend and a closed eNd, said housing further defining a fuel deliveryoutlet extending from said chamber for delivering fuel to said nozzleand a pressure relief outlet extending from said closed end of saidchamber for discharging excess fuel received from said pump, a rollingdiaphragm closing said open end of said chamber and movable away fromsaid closed end of said chamber in response to an increase in fuelpressure within said chamber, means biasing said diaphragm toward saidclosed end of said chamber, a bracket secured to said diaphragm withinsaid chamber and engageable with said closed end of said chamber forlimiting movement of said diaphragm theretoward, a valve member disposedin said chamber and engageable with said pressure relief outlet forcontrolling flow therethrough, means biasing said valve member away fromsaid diaphragm toward engagement with said pressure relief outlet, saidvalve member including means engageable with said bracket after saiddiaphragm and said bracket move a selected distance away from saidclosed end of said chamber to thereby disengage said valve member fromsaid pressure relief outlet, whereby initial displacement of saiddiaphragm less than said selected distance in response to an increase infuel pressure within said chamber increases the amount of fuelaccumulated in said chamber, whereby additional displacement of saiddiaphragm greater than said selected distance in response to an increasein fuel pressure within said chamber effects disengagement of said valvemember from said pressure relief outlet to prevent further increase inpressure within said chamber, and whereby return of said diaphragmtoward said closed end of said chamber upon a decrease in fuel pressurewithin said chamber discharges the increased amount of fuel accumulatedwithin said chamber through said fuel delivery outlet for delivery tosaid nozzle.
 2. The accumulator and pressure regulator of claim 1wherein said bracket has a plurality of slots and said valve member hasprojections received in said slots whereby said valve member may beengaged by said bracket after said diaphragm and said bracket move saidselected distance.
 3. The accumulator and pressure regulator of claim 1which further comprises means for applying a bias pressure against saiddiaphragm in opposition to the fuel pressure.
 4. In a fuel injectionsystem, a pump for delivering fuel to an injection nozzle comprising astator defining a stator chamber, a cylindrical rotor disposed withinsaid stator chamber, a slider reciprocably disposed within said statorchamber and having a cylindrical pumping chamber receiving said rotor,said slider further having a fuel inlet for supplying fuel to saidpumping chamber and a fuel outlet for discharging fuel from said pumpingchamber, said slider being responsive to an increase in fuel pressure insaid stator chamber to move from a pumping position wherein the axis ofsaid pumping chamber is eccentric the axis of said rotor toward aneutral position wherein the axis of said pumping chamber is coincidentthe axis of said rotor, means biasing said slider toward said pumpingposition, a plurality of vanes extending radially from said rotor intoengagement with said slider, an accumulator and pressure regulatorhaving an accumulator chamber connected to said slider fuel outlet forreceiving fuel from said pumping chamber, said accumulator chamberhaving an open end, a closed end, a fuel delivery outlet for deliveringfuel to said nozzle and a pressure relief outlet extending to saidstator chamber at one end of said slider, a rolling diaphragm closingsaid open end of said accumulator chamber and movable away from saidclosed end upon an increase in fuel pressure within said accumulatorchamber, means biasing said diaphragm toward said closed end of saidaccumulator chamber, a bracket secured to said diaphragm in saidaccumulator chamber and engageable with said closeD end of said chamberfor limiting movement of said diaphragm theretoward, a valve memberdisposed in said accumulator chamber and engageable with said pressurerelief outlet for controlling flow from said accumulator chamber to saidstator chamber, means biasing said valve member away from said diaphragmtoward engagement with said pressure relief outlet, said valve memberincluding means engageable with said bracket after said diaphragm andsaid bracket move a selected distance away from said closed end of saidaccumulator chamber to thereby disengage said valve member from saidpressure relief outlet, whereby rotation of said rotor within saidpumping chamber when said slider is in said pumping position may effectdelivery of fuel from said slider fuel inlet, through said pumpingchamber, said slider fuel outlet, said accumulator chamber, and saidfuel delivery outlet to said nozzle, whereby initial displacement ofsaid diaphragm less than said selected distance in response to anincrease in fuel pressure within said accumulator chamber increases theamount of fuel accumulated in said accumulator chamber, wherebyadditional displacement of said diaphragm greater than said selecteddistance in response to an increase in fuel pressure within said chambereffects disengagement of said valve member from said pressure reliefoutlet and fuel is discharged from said accumulator chamber through saidpressure relief outlet to said stator chamber to displace said slidertoward said neutral position and thereby reduce fuel delivery from saidpumping chamber, and whereby return of said diaphragm toward said closedend of said chamber upon a decrease in fuel pressure within saidaccumulator chamber discharges the increased amount of fuel accumulatedwithin said accumulator chamber through said fuel delivery outlet fordelivery to said nozzle.
 5. The pump of claim 4 wherein said one end ofsaid slider has an opening from said stator chamber to said slider fuelinlet to permit reduction of pressure in said stator chamber and therebyfacilitate return of said slider to said pumping position under the biasof said slider biasing means.
 6. The pump of claim 4 wherein said statorincludes a pressure relief passage extending from said slider fueloutlet to said stator chamber at the opposite end of said slider, andwhich further comprises a pressure responsive valve in said passagewhich permits fuel flow therethrough only when the pressure in said fueloutlet exceeds a selected value, whereby excess pressure in said fueloutlet may be relieved.
 7. The pump of claim 6 wherein said opposite endof said slider has an opening from said stator chamber to said sliderfuel inlet to allow fuel discharged past said pressure responsive valveto flow freely to said fuel inlet.